Fluorometric Determination of Small Amounts of Anthracene in Anthraquinone

Abstract

A fluorometric method for the determination of small amounts of anthracene in anthraquinone is proposed. The influence of large amounts of anthraquinone can be removed by the reaction with sodium dithionite alkaline aqueous solution due to the formation of anthrahydro quinone, which dissolves in alkaline aqueous solution.
About 10 ml of the sample solution dissolved in xylene (100, tig/m/) are taken in 50 ml separating funnel and 300 mg of sodium dithionite and 30 ml of O.5 mol/l sodium hydroxide solution are added. The air in the funnel is replaced with nitrogen. The mixture is warmed to 40° C for 10 minutes and shaken sufficiently for 15 minutes. After the aqueous phase is removed, xylene phase is dried with anhydrous sodium sulfate. The fluorescense intensity is measured at 4O^2- nm with excitation at 378 nm against 0.25 /Tim/ anthracene solution as reference standard. By this method, anthracene in anthraquinone can be determined down to O.01%. This method is not interfered with the presence of impurities, unless the amount is so large.